An Orbital Light‐Curve Model for GX 301−2

Abstract

We present the results of X-ray observations of GX 301-2 with instruments aboard the ASCA and RXTE spacecraft, as well as analysis of archival data from BATSE/ CGRO and the All-Sky Monitor on RXTE . We discuss evidence that (1) GX 301-2 has changed its spin state, perhaps entering a stochastic spin state similar to 1974-1984; (2) epochal changes occur in the constant and flaring components of the orbital light curve?a 25% increase in the overall luminosity is coincident with the changed spin state and is due to an increase in the constant component accompanied by a decrease in the near-apastron flare; and (3) the orbital light curve, in general, and timing of the preperiastron flare, in particular, can be understood as a latency effect in the GX 301-2 accretion disk.